Same situation here. XW was on facebook and classmates.com and has been for a while. She thinks its 1974 again.
Found out much later after the divorce that she has been on contact with her first boyfriend from high school and she told him she was still madly in love with him etc.
When I read your post I threw up in my mouth a little bit since my sitch is almost a mirror of yours. Luckily my kid is grown though.
Me:48 W:55 M:22 T:23 Bomb:19Nov09 S:15Jan10 D:11Feb10 EA:Confirmed on 20Apr10 Fast track to her divorcing me